Low Back Pain Treatments, Stenosis, and Nerve Tension Testing

As we wrap up the 2012 low back pain CPG by covering the treatment section, David discusses two topics the clinical practice guideline doesn't cover well: lumbar stenosis (as well as how to distinguish it from intermittent claudication) and how to bias nerve tension testing for various branches of the sciatic nerve nerves.

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Transcript

Hello and thank you for joining us for another episode of OCS Field Guide. We are now nearing the end of this series we have been doing on low back pain. We will likely return to the lumbar spine again later on in this podcast, but by now we have covered most of the biggest topics in the lumbar spine, so it is almost time for us to move on. But before we d o, there are a few more big topics to cover. So today we are finishing the low back pain CPG by discussing the “treatment” section, and along the way I want to spend a few minutes talking about some topics not covered well in the CPG: lumbar stenosis and lower extremity nerve tension testing. If you want to jump ahead to a specific topic or section, I recommend listening to this podcast on our website, physiofieldguide.com, where each episode is divided into chapters, and you can jump to the section you’re most interested in.

Let’s begin with the low back pain treatment section of the CPG. When you get to the treatment section of any CPG, there are a few big things you should be looking for. First, you should pay attention to which treatments are recommended, and which treatments are not recommended. On the most foundational level, you need to know what you should and shouldn’t choose for your patient. So then you should pay attention to when each treatment is recommended—is it only for the acute stage? Is it recommended only for a specific purpose, like short-term pain relief? And finally, you should pay attention to which treatments have the strongest evidence, and which have the weakest. It’s possible that you could get a question that makes you select the treatment with the strongest evidence from a list of four perfectly acceptable and reasonable treatment options.

So If you need a quick refresher on the way the clinical practice guidelines grade their recommendations, it’s on a scale from A to F. A is strong evidence, which means there is a preponderance of evidence from randomized controlled trials, and at least one of those trials is a high quality trial. A B-level recommendation is based on moderate evidence, which means it’s based on a single high-quality randomized controlled trial, or it’s based on a preponderance of lesser-quality controlled trials. A C recommendation is for weak evidence, which means it is based on a single lesser-quality controlled trial or a preponderance of evidence from case-controlled studies, retrospective studies, or case series. A D recommendation means there is conflicting evidence. Keep in mind that it is really hard to ask a question about a topic where there is conflicting evidence. E means there is theoretical or foundational evidence, which means the evidence comes from sources like animal studies, cadaver studies, or conceptual models. And an F recommendation is expert opinion based on the clinical experience of the CPG team. So remember that in this grading system, A doesn’t mean “use this treatment” while F means “avoid this treatment!” A means we have a good amount of evidence either for or against a specific treatment. You have to read the discussion to know which it is. And you should remember that the more evidence we have either for or against something, the more likely it is to show up on the exam.

So now for the CPG’s treatment recommendations. I’m going to cover these in order of strongest evidence to weakest evidence.

First, A-level evidence. The following treatments have A-level recommendations: manual therapy; trunk coordination, strengthening, and endurance exercises (which are sometimes referred to as stabilization exercises); directional preference or McKenzie-style repeated movement exercises; and progressive endurance exercise and fitness activities for chronic back pain. Let’s go through each in order.

When discussing the strong evidence for manual therapy, the CPG specifically notes that clinicians should use thrust manipulation to reduce pain and disability in acute low back pain. This is based on the same studies we mentioned in our last episode. The CPG also notes that there is some evidence for thrust and non thrust manual therapy in subacute and chronic low back pain, but our strongest evidence is for thrust manipulation in that group that has pain above the knee that started less than 16 days ago.

Regarding trunk coordination, strengthening, and endurance exercises—or what we commonly call motor control or lumbar stabilization exercises—we have A-level evidence for its use “to reduce low back pain and disability in patients with subacute and chronic low back pain with movement coordination impairments and in patients post–lumbar microdiscectomy.” So in addition to using these treatments for those who fit the stabilization category of the treatment-based classification, we also have evidence for its use postoperatively following microdiscectomy.

Next is directional preference or McKenzie-style repeated movement exercises. The CPG says we have strong evidence for these procedures under two scenarios: one is to promote centralization of symptoms in patients with acute back pain with referred lower extremity pain. These are the patients who fit the directional preference category of the treatment-based classification. They have referred lower extremity pain and demonstrate centralization or reduction in symptoms with repeated flexion or extension. The other time the CPG says we should use these exercises is in patients with acute, subacute, or chronic back pain with mobility deficits. In these patients with mobility deficits, these directional preference exercises are specifically to improve mobility and reduce symptoms.

Now, the CPG lists flexion-based exercises for lumbar stenosis separately from these directional preference or McKenzie-style repeated movements. These  flexion exercises for stenosis only get a C-level recommendation, and we will discuss them in a few minutes.

Finally, the last A-level recommendation is for progressive endurance exercise and fitness activities for chronic back pain. The CPG divides the chronic back pain group into two categories: chronic back pain without generalized pain, and chronic back pain with generalized pain. The idea is that those with generalized pain may have central sensitization affecting the way they perceive and respond to exercise. So the evidence indicates that these individuals need to be managed differently. For the chronic back pain patients without generalized pain, we have an A-level recommendation for moderate to high intensity exercises. For the chronic back pain patients with generalized pain, the recommendation is for progressive, low-intensity, sub-maximal fitness and endurance activities. So to reiterate: those with chronic back pain should get high intensity exercises, unless they have signs of central sensitization. Then they should get sub-maximal endurance exercises.

That wraps up the A-level recommendations.

Next, we have a B-level recommendation for patient education. I think this is a really important section, so pay attention. The CPG reads, “Clinicians should not utilize patient education and counseling strategies that either directly or indirectly increase the perceived threat or fear associated with low back pain, such as education and counseling strategies that (1) promote extended bed-rest or (2) provide in-depth, pathoanatomical explanations for the specific cause of the patient’s low back pain. Patient education and counseling strategies for patients with low back pain should emphasize (1) the promotion of the understanding of the anatomical/structural strength inherent in the human spine, (2) the neuroscience that explains pain perception, (3) the over-all favorable prognosis of low back pain, (4) the use of active pain coping strategies that decrease fear and catastrophizing, (5) the early resumption of normal or vocational activities, even when still experiencing pain, and (6) the importance of improvement in activity levels, not just pain relief.” I would expect some questions on this, because back pain is such a big part of the exam, and so much of our evidence shows that the clinical course of back pain is strongly influenced by psychosocial factors. So don’t recommended extended bed rest or provide in-depth pathoanatomical explanations for back pain. Instead, emphasize the inherent strength in the spine, explain the neuroscience behind pain perception, emphasize the overall favorable prognosis of low back pain, encourage active pain coping strategies, encourage resuming activities even while pain is still present, and focus on functional improvements, not just pain scale improvements.

Now let’s cover the C-level recommendations.

I mentioned earlier that flexion-based exercises for lumbar stenosis, which are sometimes called Williams flexion exercises, are listed separately from the directional preference category and only receive a C-level recommendation. And this is because lumbar stenosis is just a little different from other kinds of low back pain, and so when studies examine this population specifically, the results are a little different. In its conclusion, the CPG says, “Clinicians can consider flexion exercises, combined with other interventions such as manual therapy, strengthening exercises, nerve mobilization procedures, and progressive walking, for reducing pain and disability in older patients with chronic low back pain with radiating pain.”

Now, among the studies referenced in this section is an important 2006 randomized controlled trial by Whitman and colleagues comparing these flexion-based exercises and treadmill walking to a group who received manual therapy, exercises, and bodyweight supported treadmill walking. In this study, the group who received manual therapy and bodyweight supported treadmill training were much more successful than the group who did not. This study tells us a couple things that you should remember for lumbar stenosis. First, a multimodal approach that includes manual therapy and exercise is going to be best for a patient who has lumbar stenosis. So if you get an OCS question on lumbar stenosis and have the opportunity to pick a treatment that includes both manual therapy and exercise, pick that multi-modal approach! Second, there is some decent evidence here for bodyweight supported treadmill walking for treating lumbar stenosis. So although the CPG doesn’t mention bodyweight supported walking in its own category, you need to consider it as a good, evidence-based treatment option in this population.

And speaking of this treatment population, we haven’t spent a lot of time talking about lumbar stenosis specifically. And that’s mostly because of the CPG’s recommendation to avoid pathoanatomical explanations for mechanical low back pain when possible, and because the treatment-based classification system is easier to memorize when you’re not worrying about specific diagnoses. But lumbar stenosis is a low back diagnosis that is a little unique, and it deserves a few minutes of our time. I didn’t know where else to fit it into our series, so let’s talk about it here.

Recall that lumbar stenosis is a narrowing of the vertebral canal and/or the foramina that leads to nerve root compression. This causes a classic pattern of radiating lower extremity pain, burning, weakness, and paresthesias. Symptoms are typically bilateral, start at the buttocks, and spread distally to the feet. People who have lumbar stenosis will report onset of pain or cramping with standing or walking, particularly if they are in an extended position, like walking downhill. Remember that this pattern of lower extremity pain while walking is called neurogenic claudication. The pain is relieved by flexing the spine, such as walking uphill, although it can take some time for the pain to decrease.

I’m bringing this up because I would expect you to get a few questions where you have to distinguish neurogenic claudication caused by lumbar stenosis from intermittent claudication caused by peripheral vascular disease. Both involve walking symptoms that can be described as pain, weakness, or cramping in the legs and calves. So here is a review of intermittent claudication and how to distinguish it from lumbar stenosis. In intermittent claudication, the problem is blood flow. Vascular disease makes it difficult to get blood to the muscles during exertion, so symptoms are brought on by exertion and are typically relieved almost immediately with rest. (The caveat to this is that in severe PVD, the pain may persist at rest too). So since more exertion causes more severe symptoms, walking uphill, which requires more calf exertion, is more problematic in this population. Riding a bicycle, which is usually no problem for those with lumbar stenosis, may also provoke symptoms here. And since the problem is blood flow, not nerve compression, spinal position has no effect on pain. If you’re looking for a value you can identify in a question to tip you off that peripheral vascular disease is present, recall that an ABI of <1 indicates possible presence of peripheral arterial disease, an ABI of <0.9 is considered clearly abnormal, <0.8 indicates intermittent claudication may be present, and <.25 is limb-threatening.

So to reiterate the differences: neurogenic claudication caused by lumbar stenosis is going to be worse walking downhill and better walking uphill. Intermittent claudication caused by vascular disease will be worse walking uphill or riding a bike. In lumbar stenosis, the pain is relieved with spinal flexion, but it might take a while to calm down. In intermittent claudication due to PVD, the pain is relieved with rest, not spinal flexion, and—unless the PVD is severe—the pain is relieved very quickly. And finally, with stenosis, the symptoms usually start at the buttocks and move distally. With PVD, the symptoms usually start in the calves and feet and may move proximally to the thighs and buttocks.

So I would suspect that at some point you will see a case of a patient who reports leg pain or cramping or weakness while walking, and you will have to distinguish whether the cause is neurogenic claudication from lumbar stenosis or intermittent claudication from peripheral vascular disease.

How do you treat the patient if the pain is from peripheral vascular disease? We won’t veer too far off course by spending a lot of time on this here, but we do have several studies that indicate progressive treadmill walking to the point of moderate or near-maximal pain, followed by resting, and then repeating that process for up to 50 minutes per session over the course of 6 months can improve maximal walking distance in individuals with peripheral arterial disease.

So we treat lumbar stenosis with manual therapy, flexion exercises, and bodyweight supported treadmill training. We treat intermittent claudication from PVD with progressive treadmill walking to the point of moderate or near-maximal pain, followed by rest, followed by more walking.

And at this point, we’ve wandered way off course. Let’s return to the low back pain clinical practice guideline.

The CPG also gives a C-level recommendation to nerve mobilization procedures, sometimes called nerve gliding or nerve flossing. It says, “Clinicians should consider utilizing lower-quarter nerve mobilization procedures to reduce pain and disability in patients with subacute and chronic low back pain and radiating pain.” So if you are following Alrwaily’s 2016 treatment-based classification system, you’re going to use these exercises correctly in that subacute or chronic stage. I want to mention that since the CPG was published in 2012, some more studies have come out in favor of neural mobilization exercises, so if the CPG was written today, these exercises would likely be given a B or an A-level recommendation. I also want to let you know that the OCS exam item writers really, really love peripheral nerve entrapments. So you need to recognize when nerve mobilization procedures could be effective, but you will also need to know how to sensitize your testing procedures to isolate specific nerve branches. This might be a good topic to handle in an entire episode on peripheral nerve entrapments, but let’s spend a quick minute reviewing how to test nerve tension in the lower extremity.

If you’re doing a straight leg raise to test nerve tension, you’re always going to be flexing the hip with the knee in extension. You can add other pieces to that movement to stress different nervous system structures. You stress the sciatic nerve more by dorsiflexing the ankle and adding hip adduction and/or hip internal rotation. You can test the posterior tibial nerve with ankle dorsiflexion and eversion, and toe extension may further stress the tibial nerve. You can test the sural nerve with ankle dorsiflexion and inversion. And you can test the common peroneal nerve by adding hip internal rotation, ankle plantar flexion, and inversion. I would expect some questions where you have to identify which position stresses which nerve. So one more time: they all involve hip flexion and knee extension. For the sciatic nerve, add hip adduction and/or internal rotation as well as ankle dorsiflexion. For the posterior tibial nerve, add ankle dorsiflexion and eversion, possibly with some toe extension. For the sural nerve, add ankle dorsiflexion and inversion. And for the common peroneal nerve, add hip internal rotation, ankle plantar flexion, and inversion. Got it?

Alright, let’s finish up the D-level recommendation.

The CPG gives traction a D for conflicting evidence. It reads, “There is conflicting evidence for the efficacy of intermittent lumbar traction for patients with low back pain. There is preliminary evidence that a sub-group of patients with signs of nerve root compression along with peripheralization of symptoms or a positive crossed straight leg raise will benefit from intermittent lumbar traction in the prone position. There is moderate evidence that clinicians should not utilize intermittent or static lumbar traction for reducing symptoms in patients with acute or sub-acute, nonradicular low back pain or in patients with chronic low back pain.” So if you’re only using traction on those with signs of nerve root compression who peripheralize with flexion and extension, like we talked about in the treatment-based classification episode, you’ve got this down. Note that both intermittent and static traction are recommended against in patients without radicular symptoms and patients who have chronic back pain.

Hopefully you can see how all these recommendations fit very well into the treatment-based classification systems we covered in our last episode. As we wrap up, I’m going to summarize everything we’ve just discussed, and then I’ll sign off for this episode.

The CPG makes A-level recommendations for the following: manipulation for acute back pain (though mobilization also helps and manipulation might help in subacute and chronic cases too). Also, stabilization for subacute or chronic back pain in individuals who fit the stabilization classification or have had a microdiscectomy. Directional preference exercises also get an A-level recommendation for acute, sub-acute, or chronic back pain in people who fit the directional preference classification. Finally, moderate to high intensity exercise for chronic back pain patients without generalized pain, and low-intensity endurance exercise for chronic back pain patients with generalized pain also get A-level recommendations.

The only B-level recommendation is for patient education and counseling that avoids increasing the patient’s fear and emphasizes the strength of the spine, pain science, good prognosis, active coping, resuming activities even if pain is present, and return to functional goals—not just decreasing pain.

C-level recommendations are given to flexion-based exercises for spinal stenosis and nerve mobilizations. But don’t forget that a multimodal approach to lumbar stenosis including manual therapy and bodyweight supported treadmill training does better than flexion exercises alone.

Traction has the least amount of evidence, and it receives a D for conflicting evidence.

That wraps up our discussion for today as well as our overview of the low back pain clinical practice guideline. Until next time, good luck studying. And go out there and get some of that moderate- to high-intensity exercise.